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Re: {} Questions

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Ben Bacarisse <ben@bsb.me.uk> wrote:

> porkchop@invalid.foo (Mike Sanders) writes:
> 
>> Assuming any awk variant...
>>
>> 1. Is this valid? (it works with mawk, gawk, busy box awk)
>>
>>    BEGIN { debug = 1 }
>>
>>    (debug)  { code_here }
>>
>>    (!debug) { code_here }
>>
>>    END { ... }
> 
> Yes, that's valid.  You don't need the ()s round the expressions.

Thanks Ben.

>> 2. what is the name or accepted term in AWK for unamed functions,
>> main()?
> 
> I don't know what you mean.  Can you give an example?
> 
> It occurs to me that maybe you think
> 
>   (debug) { code }
> 
> is a function?  It's not.  It's just a normal pattern/action AWK pair.
> An AWK pattern can just be an expression.  That expression is evaluated
> for every input line and, if true, the corresponding action is executed.

And yet there's still more implied nuance somehow. Let me try to articulate
my thoughts...

- These types of constructs are 'auto' ran per line of input (assuming
  its not located within another user-written function) that I get.
  Perhaps a potential efficiency hit to be aware of.

- There's also the scope of variables to consider... Because any
  variable's located outside of a user-written function or conversely
  located within a 'bare naked' construct is global, or at least
  exposed to the entire script's 'world', so I want be careful here...

  I'm guessing that any construct that lacks a function signature
  is globally scoped:

  { im_global = 42 }

  while those with a function signature (located within parentheses)
  are locally scoped:

  function private(private_var1) { private_var1 = "foo" }

- And 2 more...

  $ awk '{ v="im_global" }'

  $ awk -f foo -v global=55

  Anything within the above 2 are global as well?

Just thinking aloud here so, I'll let you long time posters describe
it more lucidly.

-- 
:wq
Mike Sanders

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Thread

{} Questions porkchop@invalid.foo (Mike Sanders) - 2024-08-21 05:35 +0000
  Re: {} Questions Ben Bacarisse <ben@bsb.me.uk> - 2024-08-21 09:06 +0100
    Re: {} Questions porkchop@invalid.foo (Mike Sanders) - 2024-08-21 11:48 +0000
      Re: {} Questions Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-08-21 14:08 +0200
        Re: {} Questions Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-08-21 14:10 +0200
        Re: {} Questions porkchop@invalid.foo (Mike Sanders) - 2024-08-21 18:57 +0000
          Re: {} Questions Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-08-22 00:51 +0200
      Re: {} Questions Ben Bacarisse <ben@bsb.me.uk> - 2024-08-21 16:38 +0100
        Re: {} Questions porkchop@invalid.foo (Mike Sanders) - 2024-08-21 19:01 +0000

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